ICU获得性感染-文档资料

S.
Epidermidis
S. Epidermidi3s4%
Strept.
E. faecium
Mechanism of Resistance to Beta-lactam Antibiotics
Department of Critical Care Medicine Peking Union Medical College Hospital
Beta-lactam , m acrolide, am inoglycoside Q uinolone, am inoglycoside
3. alteration in antibiotic target site (e.g. bacterial enzym e of ribosom e)
4. m odification of bacterial m etabolic pathw ay resulting in bypass of antibiotic site of in h ib itio n
Nosocomial Infection in ICU
Common pathogens community-acquired infection and early (< 4d)
hospital-acquired infections
• Streptococcus pneumoniae • Haemophilus influenzae • Enterobacteriaceae (Escherichia coli, Proteus spp.,
• 3rd generation cephalosporins • fluoroquinolones • vancomycin
• favor the selection of inducible betalactamase producing GNB, such as Pseudomonoas aeruginosa, Enterobacter clocae, Serratia spp., and Citrobacter freundii
ICU
10%
Nosocomial Infection
Vincent et al. JAMA 2019; 374: 639-644 (EPIC)
Infection
Medicine Surgery ICU
(%)
(%)
(%)
LRTI
24
18
65
UTI
43
31
18
Soft tissue
--
11
12
BSI
15
• pulmonary artery catheterization
• central venous access • stress ulcer
prophylaxis • use of steroid • nutritional status
Nosocomial Infection in ICU
Duration of ICU stay -- EPIC data
permeability barriers
Inducible Beta-lactamase
• also called class I beta-lactamase or constitutive beta-lactamase or AmpC betalactamase
• beta-lactam interferes with normal cell wall biosynthesis, causing impaired cellular function, altered cell morphology or lysis
Mechanism of Antibiotic Resistance
1 1 .9
g lyco p Байду номын сангаас p tid e
1 1 .6
Nosocomial Infection in ICU
Previous exposure to antibiotics
• modify intestinal flora, leading to colonization with resistant bacteria
te tra c yc lin e
Does beta-lactamase confer resistance?
• The amount of enzyme products • its ability to hydrolyse the antibiotic
in question • its interplay with the cellular
10
2
Other
18
30
13
Nosocomial Infection in ICU
Predisposing risk factors
• prolong length of ICU stay
• antibiotic usage
• mechanical ventilation
• urinary catheterization
Klebsiella pneumoniae) • MSSA • Streptococci • anaerobes
Nosocomial Infection in ICU
Common pathogens late (> 4d) hospital-acquired infections
• Enterobacter spp. • Serratia spp. • ESBL-producing microorganisms • Pseudomonas aeruginosa • Acinetobacter spp. • MRSA • enterococci • fungi
EPIC Data
• a total of 45% of patients had an infection
• ICU-acquired infection
21%
• community-acquired infection 14%
• hospital-acquired infection other than
300 billion
Source: OTA Report
Nosocomial Infection in ICU
• an overall risk of 18% of acquiring an infection during ICU stay
• one of the most common causes of death in ICUs
Principle of beta-lactam action
• a rigid bacterial cell wall protects bacteria from mechanical and osmotic insult
• beta-lactam inhibits PBPs
– preventing formation of the peptide bridges – producing weakened wall – activating cell wall degrading enzymes -- autolysin
1996
Citrobacter Proteus
1997
1998
1999
Enterobacter P. Aeruginosa
E. Coli Stenotrophomonas
Emerging Pathogens
Candida 10%
Grampositive rod
32%
Gramnegative bacilli
5. prom otion of antibiotic efflux from cell, preventing intracellular accum ulation of a n tib io tic
M acrolide, quinolone beta-lactam , am inoglycoside Trim ethoprim e, sulphonam ide
80%
60%
40%
20%
0%
1995
1996
1997
1998
1999
Gram-negative bacilli Gram-positive rods Fungi Other
100%
Gram-negative pathogens in ICU, PUMCH
80%
60%
40%
20%
0% 1995
Acinetobacter Klebsiella
length of ICU stay
OR for NI
1 - 2 days
1
3 - 4 days
3
5 - 6 days
6
> 21 days
33
Nosocomial Infection in ICU
Use of Antibiotics -- EPIC data
• of 10,038 patients, 62% received antibiotics for either prophylaxis or treatment
O rganism /Antibiotic MRSE MRSA Enterobacter Am picillin-resistant E. coli Im ip en em -resistan t P. aeru g in o sa Vancom ycin-resistant Enterococcus Estim ated total costs O ther associated costs
M echanism
Exam ple
1. bacterial enzym e production resulting in destruction or structured m odification of a n tib io tic
2. alteration in bacterial m em brane to reduce antibiotic perm eability
A n tib io tics
% o f p ts w ith a b x
ce p h a lo sp o rin s
44
broad-spectrum P C N
2 4 .3
a m in o g lyco sid e
2 3 .9
m e tro n id a zo le
1 7 .1
flu o ro q u in o lo n e
Nosocomial Infection in ICU
European Prevalence of Infection in Intensive Care Study (EPIC)
• Held on April 29, 1992 • an overall of 9567 patients • from 1417 ICUs
ICU-acquired Infection and
Strategy of Antibiotic Therapy
Dept of Critical Care Medicine Peking Union Medical College
Hospital
Cost of Hospital Stay Associated with Resistance
O verall total estim ated costs Value of A H um an Life?
U SD (m illion) 239 122 119 83 61 37
0.7-1.2 billion Secondary infections
D ays of w ork lost Posthospital care O ther m ajor costs
EPIC Data
most common pathogens
• S. aureus
30%
• P. aeruginosa
29%
• Coagulase-negative staphylococci 19%
• E. coli
13%
• Enterococcus spp.
12%
Pathogens of nosocomial infection in ICU, PUMCH 100%
58%
Gram-negative bacilli
Gram-positive rod
Data from ICU, PUMCH 2019
Candida
Emerging Pathogens
E. faecium 6%
E. faecalis 23%
S. aureus 28%
Strept. 9%
S. aureus E. faecalis